Hantavirus was first recognized as an infectious disease in the early 1950s when a cluster of 3,000 United Nation troops stationed in Korea was struck by a mysterious illness. Ten to fifteen percent of those infected perished, and though the exact etiologic agent was not discovered for two decades, it was suspected that rodents served as the main epidemiologic vector. Infection was associated with fever, hypotension, renal failure, thrombocytopenia, and disseminated intravascular coagulation (DIC). The clinical syndrome became known as hemorrhagic fever with renal syndrome (HFRS), formerly Korean hemorrhagic fever, and the virus was named Hanta after the Hantaan River of Korea. Over the ensuing years, several other etiologic agents of HFRS such as the Seoul, Puumala, and Dobrava viruses, were discovered across Europe and Asia.
Though antigenic evidence of Hantavirus remains widespread among rodents across the United States, only a handful of cases of HFRS was ever identified in the states.
Symptoms of HFRS usually develop within 1 to 2 weeks after exposure to infectious material, but in rare cases, they may take up to 8 weeks to develop. In Nephropathia epidemica, the incubation period is three weeks. Initial symptoms begin suddenly and include intense headaches, back and abdominal pain, fever, chills, nausea, and blurred vision. Individuals may have flushing of the face, inflammation or redness of the eyes, or a rash. Later symptoms can include low blood pressure, acute shock, vascular leakage, and acute kidney failure, which can cause severe fluid overload.
When to See Your Doctor
If you have unexplained fever, body aches, abdominal pain, diarrhea, headaches, dry cough or severe breathing difficulty, you should see a healthcare provider. This is especially true if you live in the southwestern US and are exposed to large rodent populations, their nesting material and waste.
The severity of the disease varies depending upon the virus causing the infection. Hantaan and Dobrava virus infections usually cause severe symptoms, while Seoul, Saaremaa, and Puumala virus infections are usually more moderate. Complete recovery can take weeks or months.
The course of the illness can be split into five phases:
This syndrome can also be fatal. In some cases, it has been known to cause permanent renal failure.
Transmission by aerosolized rodent excreta still remains the only known way the virus is transmitted to humans. In general, droplet and/or fomite transfer has not been shown in the hantaviruses in either the pulmonary or hemorrhagic forms.
For Nephropathia epidemica, the bank vole is the reservoir for the virus, which humans contract through inhalation of aerosolised vole droppings.
HFRS is difficult to diagnose on clinical grounds alone and serological evidence is often needed. A fourfold rise in IgG antibody titer in a 1-week interval, and the presence of the IgM type of antibodies against hantaviruses are good evidence for an acute hantavirus infection. HFRS should be suspected in patients with acute febrile flu-like illness, kidney failure of unknown origin and sometimes liver dysfunction.
There is no cure or vaccine for HFRS. Treatment involves supportive therapy including renal dialysis. Treatment with ribavirus in China and Korea, administered within 7 days of onset of fever, resulted in a reduced mortality as well as shortened course of illness.
Rodent control in and around the home remains the primary prevention strategy, as well as eliminating contact with rodents in the workplace and campsite. Closed storage sheds and cabins are often ideal sites for rodent infestations. Airing out of such spaces prior to use is recommended. Avoid direct contact with rodent droppings and wear a mask to avoid inhalation of aerosolized rodent secretions.
HFRS is primarily a Eurasian disease, whereas HPS appears to be confined to the Americas. The geography is directly related to the indigenous rodent hosts and the viruses that coevolved with them.
Although fatal in a small percentage of cases, nephropathia epidemica is generally milder than the HFRS that is caused by hantaviruses in other parts of the world.
Stay connected to myschoollibrary for more